Method of projecting images and apparatus therefor



M ch 9- G. H. s. M NAlR "w1:,704',756

AND APPARATUS THEREFOR METHOD OF PROJECTING IMAGES 2 Sheets-Sheet 1.

Filed Feb. 17, 1925 m M w A TTORNE Y.

March 12, 1929. G. H. s. M NAIR 1,704,756

METHOD OF PROJECTING IMAGES AND APPARATUS THEREFOR Filed Feb. 17, 1925 2 Sheets-Sheet 2 lnvenivr #770 IP/VE' Y Patented Mar. 12, 1929.

TENT QFFICE.

GEORGE E. STANSER MCNAIR, 0E ESSEX FELLS, NEW JERSEY.

METHOD 0E PROJECTING IMAGES AND APPARATUS THEREFOR.

Application filed February This invention relates to a method of projecting images by reflection a nd absm'ption of light and to apparatus therefoiu characterized in part by llldillfilltit)?! of the optical principles and. media disclo-cd in U. S. Pat cnt No. 1.473.913 to Georg H. Stanscr Mc- Nair et al., dated Nov.

The present invention has for objects the production of a magnified representation hf the indicating elements of a precision instrument; to facilitate easy and accurate readings of \LrlZll indicating. measuring and the like device and to produce a reflected and magnified image of relativelv movable parts within comparativel small compass, that to say. within dimensional lim ts otherwise heretofore unattained.

\Vith the above recited objects in view and others as hereinafter pointed out, my invention consists in the following steps; in illuminating an object and its immediate background by light rays caused to fall thereon after passage through a lens element of the divergent class: causing the reflect-ion either of the rays falling upon the obj ot or of the rays falling upon the background, and the absorption of the non-reflected 'ays; and intercepting the reflected rays by a receiving surface or screen, which may be either translucent or opaque, where on the image is thereby displayed in silhouette, either as lightor dark or conversely. as prearranged. without inversion or substantial loss of definition. and preferably in magnified form as the normal consequence of a divergent lens and a plane reflecting background. As will be readily understood, by substituting a curved in lieu of a plane surface as a backgrouinl. the reflected image may he dimensionally varied. in that a convex reflecting surface will amplify the normal magnification in accordanre with the degree of convexity. and a concave reflecting nllifdcc will diminish the normal magnificat on in acccrdam'e with the deg ee of conravity.

in the accompanying drawings l have illustratcd tliagrammaticallv an optical system and the related elements all ording the preferred embodiment of means adapted to practice my method, in which liigure l is a plan. View of the light source, the partially screened double concave lens, the reflecting and the absorbing object-surfaces, and the receiving surface; Figure 2 is a view, partly sectional, perpendicular to the plane of Fig 17, 1925. Serial No. 9,784.

ure 1, and lying in the several planes indirated by the broken line AA of Figure 1; Figure 3 a diagrammatic view, as in Figure 1. showing the projecting elem-buts so placed that the optical axis is angularly d sposed relatively to the plane of the reflecting surface; and Figure is a similar view of the same disposition and employing a coir ve}: reflecting surface.

Like reference characters indicate like parts throughout the several figures, in

which i i a oncentrated light source, 2 a light proof box. and 3 a lens element of tho divergent type; are reflecting surfaces. 3, 5 are stationary non-reflecting .dll'titltQr'. shown as points of a fixed scale, and (3 is a movable non-reflecting ruriisn-e. shown as a pointer mounted upon the rotatable shaft 7'; 8 is the image-receiving surface. S). 9 are the light rays emanating from the source 1; it), It) are these rays refracted by the lens 3; i], it are the reflected rays; and the interrupter-l lines 12, 12 indicate the shadows cast as the result of the absorption. of the refracted rays 1t) falling upon the non-reflecting or shadow-casting surfaces 5, 5, prodncing the corresponding but magnified imagenreas 13, 13 upon the imagercceiving surface 8. In l igure 8, the elements 1,, 2 and 3 are so disposed angularly relative to the plane surface d that the receiving surface 8 at. one side thereof, whereby the masking of any part of the receiving surface by the light proof box avoided, In Figure 4, the receiving surface 4 is shown as convex, and the divergence of the rays rcilctcd therefrom is increased in correspondence with the degree of curvature of the surface 4, whereby the magnification of the reflecting surface is increased and the image or shadow 'rea received is correspondingly enlarged.

The reflecting surface preferred is a sur face -.\lll(.l1 reflects light without material persion. such as nitro-silvcr. quick-silver.

-uhun metal or stellite. the advantage results that a small and compact illuminator for dialsnnd the like.

of indicating instruments is possibl permitting precise readings of their scales.

The magnified images permit accurate observations from a distance of the relation l'ictwetni the indicating factors.

As Will be obvious, the reflecting surface may be interrupted by non-reflecting areas either formed in the plane thereof or superimposed thereon. Thus these light absorptivc markings may consist of a hole in the reflecting surface or of a transparence therein; or of an imposed screen. In any case, these will he of any def ed configuration. Similarly. screening marks affording the contrast desired will also he obtained by superpo ineseiiii-absorptive or sem ob cur int: materials upon the light reflecting surface Such transparent or translucent ins-- terrals may be colored if and desired, and will of course produce correspondingly coiorcd projections of the image upon the eeiving surface.

As above su rested, it is immaterial for the purpose ot image casting Whether the scale elements have non-reflecting surfaces with the scale laicl-igrouutl a non-retlccing surface; or whether the scale indicia pre i reflecting; surfaces upon a non-rethciug field. The contrast is the essential.

A particular utility for my method and devices employing, sam is that aff-rirdcd by the lecture fiel Speakers desiring; to demonstrate to their audlen'ics nicctic of measurement by in triimcnts of i i can project these readings upon a suitable wall of the room without other special zip-- paratus. Thus, in lieu of the auditors tiling: past the measuring instrument to see a d read its indications. all changes and va ia tions in th observed demonstration are visible simultaneously to all. Not only is a simultaneous and continuous ohse ration afforded to all, but a great saving); of time is effected as compared with individual 0;;- amination.

In power and the like installations. morons meters require constant obscrvaii. .3. It is not usually possible to assemble all these conveniently at a single place in a station within eye-range. By use of devices employing my invention, it i practicahlc to read all meters and the like from one point of ohser 'ation with otherwise unaided vision.

Other features of utility and advantage will occur to tho e employed in the common cial and practical application of the arts and sciences requiring inspection and ohsecvation of the forces actin" and niea urei r i of the magnitudes of tlu forces.

The particular embodiment of mean: for the realization of inv improvcd projcctiug images by iuae niticd rcllccti i not of llltulu'lli. In l a'arcs L 2 and l lll'l't is shown a rotating pointer as typiral of the moving element of an indicating: scale, but it is inimaten'al, obviously. which indicati element moves so long as change of relative position occurs between a fixed and a movable element.

By the phrase reflecting surface as above employed, I intend to define the rcfleeting surface to be used as one adapted to reflect such an amount of the light received thereon will produce he result desired. As will be obvious, the results will he attained by the maximum reflect power.

lla'ing thus described my invention, I

claim as new:

1. The n'ietl sisting in inil rays from a 7 source, receiving a pi rt of these divcrglg'ci t rays upon a surface having; adjacen areas, one of which is the ol'ijccti to be pioicctcd, one of said l of projecting an image consing the divergence of the *cntraied liogl t areas being of light reflective and one if light ab orptive capacity; and receiving: upon a second surface the reflected rays.

2. In an optical projector, a light source. an apcrlurcd housing th u'efor screening: saiil source, a lens of the diverging ty' mounted in the aperture in said housing, a reflecting surface situated in the optical path of said lens, and a fixed uon-retl cling area upon said reflecting surface, whereby the transmitted falling upon the non-reflecting :Hi a are absorbed. and those falling upon the reflecting surface are re lected; a moreable nona'eilecting surface lying in a plane substantially parallel to that of the reflecting surface and adapted to overlie a portion thereof, and means for moving: such noureliec'lingg surface ov r said reflecting surface.

3. In an opti fal projector, a light source. an apcrtilrcd housing therefor screening said source. a lens of the divergent type mounted in the aperture in said housing, reflecting surface situated in the optical path of said lens. and a fix d non-reflecting area upon said retl ctingr surface, whereby the transmitted rays falling upon the non-rellccti ur re a sorhed, and those fal ing); upon lecting surface are reflected: a move {llJlt non-reflecting surface lying! in a plane, substantially parallel to that of the reflecting surface and adapted to overlie a portion thereof. means for moving such non-reflect in g' surf-arc over sa d collecting r-tllfzlt't, and a screen in the path of the reflected ravs pted to receive same. i

l. in an optical p o iccioig a light f( lil( an :uiertured housing thrnrfm: a lens of the 1l '},1'tt i tvpe mourned in the aperture in said hou ing. a rclle 't ua" surface pov iioimi in thr optical pa h of said lens. of uou-rcllc ia plurali r tin ellering! freely more i surface and means for movin same. and a screen adapted to receive the magnified images of said nonrcflecting areas when outlined hy the proicctcd rays as reflected from the said reflectin surface.

*' oicoaon H. sT'ANsna MCNAJR.

i ahle over s-aid rctleci 

